3GPP third generation partnership project
ACK acknowledge
ACCH associated control channel
ARFCN absolute radio frequency channel number
BCCH broadcast control channel
BW bandwidth
CDM code division multiplexing
CQI channel quality indicator
C-RNTI cell radio network temporary identifier
DL downlink (eNB towards UE)
eNB EUTRAN Node B (evolved Node B)
EPC evolved packet core
EUTRAN evolved UTRAN (LTE)
FDD frequency division duplex
FDMA frequency division multiple access
FDPS frequency domain packet scheduler
HARQ hybrid automatic repeat request
HO handover
LTE long term evolution
MAC medium access control
MME mobility management entity
MM mobility management
NACK not acknowledge
Node B base station
O&M operations and maintenance
OFDMA orthogonal frequency division multiple access
PCI physical layer cell identification
PCID physical layer cell identification
PDCP packet data convergence protocol
PDU protocol data unit
PHY physical
PRB physical resource block
RB radio bearer
RLC radio link control
RRC radio resource control
RRM radio resource management
SC-FDMA single carrier, frequency division multiple access
SCH synchronization channel
SDU service data unit
S-GW serving gateway
SN sequence number
TDD time division duplex
TTI transmission time interval
UE user equipment
UL uplink (UE towards eNB)
UMTS universal mobile telecommunication system
UTRAN universal terrestrial radio access network
This section is intended to provide a background or context to the exemplary embodiments of the invention that are recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
Communication networks typically operate in accordance with a given standard or specification which sets out what the various elements of the network are permitted to do and how that should be achieved. For example, the standard may define whether the user or more precisely, user equipment is provided with a circuit switched service or a packet switched service. The standard may also define the communication protocols which shall be used for the connection. The given standard also defines one or more of the required connection parameters. The connection parameters may relate to allowable connections or to various features of the connection. Further, the standard may also define which cells a mobile station should select or avoid.
In other words, the standard defines the “rules” and parameters on which the communication within the communication system can be based. Examples of the different standards and/or specifications include, without limiting to these, specifications such as GSM (Global System for Mobile communications) or various GSM based systems (such as GPRS: General Packet Radio Service), AMPS (American Mobile Phone System), DAMPS (Digital AMPS), WCDMA (Wideband Code Division Multiple Access) or CDMA in UMTS (Code Division Multiple Access in Universal Mobile Telecommunications System) and so on.
A communication system known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA) has been under development within the 3GPP. The DL access technique is OFDMA, and the UL access technique will be SC-FDMA.
The exemplary embodiments of the invention may relate to the more recent 3GPP ‘Long Term Evolution’ (LTE). In LTE, the bandwidth of signals is high (typically >5 MHz), which means that there will be very dense frequency use, and base stations will likely use a carrier frequency that is also being used by a close neighbor.
One specification of interest is 3GPP TS 36.300, V8.3.0 (2007-12), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Access Network (E-UTRAN); Overall description; Stage 2 (Release 8).
FIG. 1 reproduces FIG. 4 of 3GPP TS 36.300, and shows the overall architecture of the E-UTRAN system. The E-UTRAN system includes eNBs, providing the E-UTRA user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UE. The eNBs are interconnected with each other by means of an X2 interface. The eNBs are also connected by means of an S1 interface to an EPC, more specifically to a MME (Mobility Management Entity) by means of a S1-MME interface and to a Serving Gateway (S-GW) by means of a S1-U interface. The 51 interface supports a many-to-many relation between MMEs/Serving Gateways and eNBs.
The eNB hosts the following functions:
functions for Radio Resource Management: Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic allocation of resources to UEs in both uplink and downlink (scheduling);
IP header compression and encryption of user data stream;
selection of a MME at UE attachment;
routing of User Plane data towards Serving Gateway;
scheduling and transmission of paging messages (originated from the MME);
scheduling and transmission of broadcast information (originated from the MME or O&M); and measurement and measurement reporting configuration for mobility and scheduling.
The exemplary embodiments of the invention at least address issues resulting from the use of dense frequencies by, but not limited to, an LTE-type network.